Absorption width

The parallel component of the probe transmission change is plotted in Fig. 17 in the range 2850-3650 cm 1 for different delay times (left-hand ordinate scales, experimental points, calculated solid curves). The transient spectrum during the excitation process, to = 0 ps, is depicted in Fig. 17a. A bleaching at the frequency position of 2974 cm-1 is shown because of the excitation of the CH vibration. The excess population of the upper level v = 1 can be directly monitored from the induced absorption around 2952 cm-1 and is attributed to excited-state absorption (width of 17 2 cm-1). The bleaching signal at lower frequencies indicates... 

To find out the stabilization effect of polyelectrolytes, silver nanoparticles coated with PAH or PEG at concentrations either 1 mg/ml or 5 mg/ml were examined in 0.5 M NaCl, 0.1 M NaCl or 0.01 M NaCl by UV-Vis spectroscopy. For each type of polyelectrolytes prepared at the concentration of 1 mg/ml independently from their molecular weight and sodium chloride concentration the UV-Vis measurement data revealed most broad absorption bandwidth. The narrow absorption bandwidths were related to both PAH (15 kDa) and PEG (8 kDa) at the same concentration 5 mg/ml in 0.01 M NaCl. Silver nanoparticles modified with 5 mg/ml PAH and 5 mg/ml PEG in 0.1 M NaCl presented narrow absorption widths and relatively high absorbance intensity. Furthermore, PEG coated silver nanoparticles revealed better UV-Vis absorption results among mentioned polyelectrolytes. 

If absorption widths such as or happen to be large in comparison with the term (F —Fres) in the single level formula (9.16), then the cross section for an (wa) or [np) process becomes... 

As we have already noted (Sect.6.1.1), a well-collimated atomic beam displays a very small absorption width perpendicular to the atomic beam. As shown in Fig.9.35, the collimation ratio C for an atomic beam is defined as... 

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